This invention relates generally to footwear, and more particularly to a shoe having incorporated therein a special leaf spring-like member which is formed of a fiber reinforced polymeric material for absorbing and releasing energy during each step.
A variety of approaches have been taken toward relieving the stresses which are imposed on a human foot during walking and running. Known approaches utilize resilient, spring-like arrangements which absorb and release energy during each step of walking or running. The known arrangements store and release energy via resilient members. Many of these are arranged to operate in a direction which is orthogonal to the sole of the shoe. Some employ strips, or plates built into the shoe sole, or an orthotic in the shoe. Examples of prior constructions are shown in U.S. Pat. No. 3,039,207 and 4,231,169, British Patent Specification 56,011/73 and German Patent Disclosure 31 26301, with orthotics being set forth in U.S. Pat. No. 4,360,027, 4,612,713 and 4,628,621.
In a recent U.S. Pat. No. 4,858,338 is described a particular type of insert wherein a strip extends from the outer (lateral) heel area to the large toe area where it forms a rocker bottom to cradle the first metatarsal head. A second strip extends from the four small toes to the arch area at the opposite lateral border of the sole.